David Johnson

Professor David Johnson

Research Fellow

Organisation

Bangor University

Research summary

The research area in which I am involved is environmental biotechnology, particularly that relating the the global mining industry. Essentially, I am attempting to develop new and improved biotechnologies that can be adopted not only by my immediate partner (Rio Tinto) but also by other industial companies and regulatory authorities (e.g. the Environment Industry) to reduce the negative impacts of mining on the environment in terms of energy use and pollution, and also to promote recovery of metal resources that are currently contained in "waste" metals. The approach uses microbiological systems, including new species and consortia of benign bacteria, in a number of different applications. On the one hand, I am looking to understand better, and thereby improve, a technology known generically as "biomining", in which specialist bacteria that can break down certain minerals are used to extract metals (copper, gold and others) from ores. This is an alternative to energy-demanding smelting of ores (the bacteria work effectively at relatively low temperatures).

The flipside of this is using microbial communities to minimise pollution associated with mining. One area I am researching is how waste rocks and tailings generated by mining can be bio-engineered to minimise or prevent a global and severe form of water pollution which results in streams draining active and abandoned mines being acidic and enriched with dissolved metals, and therefore highly toxic. Tied in with this is the development of simple and low-cost microbiological systems that could be used to recover metals from these waste waters. Currently most of streams that drain mine sites are remediated (if at all) with chemicals, producing bulky sludges that require careful disposal in land fill sites designated for hazardous wastes. The approach under development would facilitate the the reovery and recycling of these metals, thereby turning what are currently regarded as waste materials into a resource.